[R] adding an ellipse to a PCA plot

[Lukas Baitsch]

Dear John,

Thanks, this actually works just fine! much easier than the ellipse-package!

Lukas

On Monday, June 6, 2011, John Fox <jfox at mcmaster.ca> wrote:
> Dear Lukas,
>
> You might try the dataEllipse() function in the car package.
>
> I hope this helps,
>  John
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>> On Behalf Of Lukas Baitsch
>> Sent: June-06-11 10:33 AM
>> To: r-help at r-project.org
>> Subject: [R] adding an ellipse to a PCA plot
>>
>> Hi,
>>
>> I created a principal component plot using the first two principal
>> components. I used the function princomp() to calculate the scores.
>> now, I would like to superimpose an ellipse representing the center and
>> the 95% confidence interval of a series of points in my plot (as to
>> illustrate the grouping of my samples).
>>
>> I looked at the ellipse() function in the ellipse package but can't get
>> it to work. the princomp()-function gives me the scores of each point,
>> so I can calculate the mean and the 95%-CI, but I can't integrate this
>> into the ellipse()-function). Is there a better way of doing this or can
>> someone help me figure out this function?
>>
>> best regards,
>>
>> Lukas
>>
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>
>